Build Your Own Universe Leaflet

8/18/2019 Build Your Own Universe Leaflet

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For more information on our outreach activities, go to our websitewww.ph.qmul.ac.uk www.sepnet.ac.uk/outreachor email us at [email protected]

BUILD YOUR OWN UNIVERSEYou will need:

At least 10,000,000,000,000,000,000,000,000,000,000,000,00

0,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 xDown quarks

At least 10,000,000,000,000,000,000,000,000,000,000,000,000,00

0,000,000,000,000,000,000,000,000,000,000,000,000,000,000 xUp quarks

At least 10,000,000,000,000,000,000,000,000,000,000,000,000

,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 xElectrons


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Just after the Big Bang, the expanding Universe was a very hot, very dense jumble of different particles,smaller than atoms and molecules – much, much smaller than a grain of sand. It was so hot (more thanone hundred thousand million degrees Centigrade!), that atoms could not survive in the intense heat.Instead, the Universe was made up of particles called ‘quarks’. These intriguing particles make up everythingaround us, and normally stick together in groups of two or three, but at the very beginning of the Universe,they could y about freely. There were also lots of electrons, the things which give us electricity by movingthrough wires, as well as their antimatter partners, positrons. Antimatter is just like matter, except thatit has the opposite charge – so a positron is just as heavy as an electron, but has a charge of +1.

Photons are particles of light. This may seem strange, but if you imagine particles of light bouncing offobjects into your eyes, it makes a bit more sense. Actually, light can be thought of as either a particle or awave, depending on the situation. The last type of particle in this mix is the ghostly neutrino, a very lightparticle, which does not affect normal matter very much. Physicists call this jumble the particle ‘soup’.

TIME = BEFORE 0.01 SECONDS

Up quark

Down quark

Electron

Positron

Photon

Neutrino


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TIME= 3 MINUTES - 20 MINUTES

Neutron

ProtonProton

Positron

+

Deuterium –a proton and aneutron

Proton

+

Now the Universe is a little cooler, protons and neutrons start to stick together, making heavier elements,like helium, and releasing energy. This process is called fusion. This process carries on until the Universe hasgrown so big that it is too cold for this process to continue.

We can estimate how much of each element this process would have made, and comparing these estimatesto what we see gives us the best evidence for the Big Bang theory.


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TIME = 379,000 YEARS

For the rst time, temperatures are cool enough for electrons to stick to the nuclei formed in the rst 20minutes after the Big Bang. The most important thing about this is that it means that light can travel withouthitting anything. If you were in the Universe before atoms formed, you wouldn’t have been able to see yourhand in front of your face, because light bouncing off your hand would bump into other things before it got toyour eye, like on a very foggy day. When atoms form, light can travel in straight lines straight from your handto your eye, and you would suddenly be able to see clearly. The light which escaped at this time can still beseen today, as the Cosmic Microwave Background, which provides further evidence for the Big Bang.

Hydrogen atom

Helium atom


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TIME = ?

At the end of the Universe,matter will either keep

ying apart

Or come backtogetherin a big ‘crush’

We really don’t know what will happen at the end of the Universe. It is possible that there won’t be an end, andthat all of the galaxies will go on ying apart (like they are now) forever, and the Universe will continue to getbigger and bigger. Another theory is that at some point, the Universe will start to get smaller, and all of the stuffin the Universe will y back together in a big crunch. But don’t worry – we don’t know when it will be, but it willcertainly be billions of years from now!

Build Your Own Universe Leaflet

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